Communication systems often use transmission signals focused around a carrier frequency of a defined channel. Information is conveyed by representing the information with a modulation based on amplitude, phase, frequency and/or combinations thereof. The information is sent by one or more signals over a band of frequencies around the carrier frequency.
A radio frequency (RF) power amplifier is often used for modulations, such as amplitude modulation. The RF power amplifier is required to operate over wide ranges of frequencies and power levels.
Ideally, RF power amplifiers would be linear and have an output that is a linear value of an input. However, RF power amplifiers typically exhibit some type of non-linearity in their behavior. This non-linearity results in non-linear variations of the output signal compared to the input signal. The non-linear variations degrade communications and increase power consumption.